Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda)
"LEED Interpretation" "1579" "2006-10-03" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc8.1 - Daylight and views - daylight 75% of spaces" "For an elementary school project registered under NC 2.1, we are targeting EQ 8.1 and can demonstrate that some regularly occupied spaces meet the daylighting requirement using the calculator/formula in the reference guide, but some do not. The spaces that don\'t comply test well using a light meter. My questions are: 1.) Is it permissable to demonstrate credit compliance using a hybrid approach: The calculation/formula in spaces where that demonstrates compliance and actual measurements where it does not? 2.) What is the correct and prescribed procedure for taking measurements? The reference guide does not provide one. I\'m assuming clear sky conditions and measuring with a light meter on the same size grid required for daylight modeling are part of the protocol - what else? Is the procedure described anywhere? Can you provide the referenced standard for testing or a description of the procedure?" "Yes, it is permissible to use both calculations and actual measurements in order to demonstrate compliance with EQc8.1 requirements. The protocol for taking measurements is outlined in the LEED-NC v2.2 Reference Guide which states that measurements must be taken on a 10-foot floor grid for all occupied spaces and must be recorded on building floor plans. Per the daylight modeling protocol, measurements should be taken 30"" off the floor, under clear sky conditions at noon. Please document the time of year the measurements were taken. Calculations should be taken at solar noon. This is the time of day that divides the daylight hours in half (between sunrise and sunset). Using this definition, daylight savings does not need to be taken into account. Since all measurements can\'t possibly be made all at once right at noon, take them within a reasonable timeframe before and after noon (i.e. between one hour before noon and one hour after noon) and do not take measurements in direct sunlight. Records of indoor light measurement must demonstrate a minimum daylight illumination level of 25 footcandles. Applicable Internationally." "None" "None" "X"
"LEED Interpretation" "1691" "2007-04-20" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc8.1 - Daylight & views: daylight 75% of spaces" "We are designing an academic building for a university client. The building contains offices, student areas, classrooms, auditoriums and specialized labs. We have organized the building to maximize daylight throughout, however, many spaces in the building are unoccupied much of the time, when the are occupied, it is typically for a one hour duration. Credit 8.1 requires that 75% of all regularly occupied spaces have the minimum 2% day lighting factor. Regularly occupied spaces are defined as areas where workers are seated or standing as they work inside a building. Some of the specialized teaching spaces in this building are designed to accommodate sensitive audio visual recording equipment for observing and documenting student performance. Other spaces, such as the auditorium and lecture halls, are designed specifically for high tech audio visual presentations and distance learning. The AV requirements for these rooms are not compatible with ample daylight. In addition, these spaces are unoccupied much of the time, and occupants are typically only in the rooms for a one hour duration. In our opinion, these rooms do not qualify as ""regularly occupied"" spaces. Our building is on a sloped site so the lowest floor is built into the hill on one side. Doing this enabled us to reduce the footprint of the building and the impervious area. We grouped some of the very specialized simulation labs against the basement wall built into the hill. These labs, if they had windows, would have blackout shades drawn all the time as natural daylight would negatively impact the simulation work, observation and recording. These labs will be unused for a substantial portion of the day; when they are used, the simulation sessions typically last for two hours or less. Every regularly occupied office or student area has a window that exceeds the 2% daylight factor. There will be a group of office spaces for part time faculty. These spaces will be largely un-used except for a couple of hours on the days the part-time faculty member is in the building to teach a class and meet with students. In our opinion, these are not ""regularly occupied"" spaces. We want to confirm our interpretation that itinerantly occupied auditoriums, classrooms, simulation labs and part-time faculty offices are not ""regularly occupied"" spaces for the purposes of this credit." "This CIR is inquiring if auditoriums, classrooms, simulation labs, and part-time faculty offices can be excluded from compliance with the requirements of EQc8.1 based on intermittent occupancy schedules and activities that are hindered by daylight. The applicant has indicated that in some of these spaces the activities would be negatively impacted by the presence of daylight. The credit requirements for EQc8.1 specifically exclude spaces where tasks would be hindered by the use of daylight. For all questionable spaces to be excluded, please clearly delineate the areas of the project being excluded from the calculations and provide a brief narrative describing the rationale and assumptions made for each excluded area in the certification documentation for this credit. It appears from the information provided in this CIR that only the simulation labs may fall under this exception. Auditoriums, classrooms, and offices often benefit from the introduction of daylight. While daylight may not be desirable for some of the stated uses, such as slideshows, there are other uses that would benefit from having daylight. It may be possible to include daylight controls in the design of the space to allow daylight when desired while providing control when the daylight hinders operations. There are many excellent examples of daylit auditoriums, classrooms, and offices, and the narrative provided in the CIR request does not provide a compelling argument to justify the exclusion of these spaces from the daylight calculations. Applicable Internationally." "None" "None" "X"
"LEED Interpretation" "1727" "2007-04-10" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc8.1 - Daylight and views - daylight 75% of spaces" "One wall of our building is a curtain wall. This curtain wall contains 4 different types of glazing, each with a different visible transmittance value, all within one room. We propose using the average visible transmittance value of the four types of glazing to do daylighting calculations for areas adjacent to the curtain wall. Please advise whether this approach is acceptable." "No, the method described of taking the overall average visible transmittance value of all four types of glazing within the curtain wall and using it for all areas adjacent to the curtain wall is not an acceptable means of calculating the daylight factor of the areas in question. However, doing a weighted average of the visible transmittance value (Tvis) of all the glazing classified as daylight glazing and a weighted average of the visible transmittance values of all the glazing classified as vision glazing on a room by room basis would be acceptable. This methodology would effectively take into account the window geometry and associated minimum visible transmittance values. Alternatively, the project team may elect to perform a daylight simulation model to demonstrate credit compliance. See the LEED NC v2.1 EQc8.1 ruling dated 6/21/2004 for guidance on pursuing this approach. Applicable Internationally." "None" "None" "X"
"LEED Interpretation" "1791" "2007-05-30" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc8.1 - Daylight & views: daylight 75% of spaces" "We are writing to clarify the role of dedicated theater spaces in Credit EQ 8, Daylighting & Views calculations. Dedicated theaters (as opposed to multi-purpose rooms) are used solely for theatrical performance and rehearsal. The intent of a theater is to exclude all natural light and views so that lighting and audience attention can be focused on the stage. Other spaces in this project (adjacent office spaces, workshops, etc.) will be daylit per the intent of the credit. Is it acceptable to remove the dedicated theater spaces from the daylight and views calculation?" "Occupants in a theater, including activities such as seating, cleaning and stage work, will benefit from daylight, however, a 2% daylight factor and access to views may be inappropriate. Dedicated theater space can qualify as a daylit space in credit calculations if the daylight design meets the recommended illuminance of 10 footcandles as noted in the IESNA Lighting Handbook Reference & Application. To document compliance, submit a daylight simulation model or daylight measurement of the theater space. Dedicated theater space may be excluded from EQc8.2 calculations for access to views. If daylighting is not provided, the space can be excluded from the credit calculations along with a narrative describing theatre activities and how daylighting will hinder these activities. Applicable Internationally. " "None" "None" "X"
"LEED Interpretation" "1925" "2007-12-06" "New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc8.1 - Daylight and views - daylight 75% of spaces" "We are developing a design for a medical office building for a community health clinic. We are pursuing a LEED SILVER certification under the LEED NC 2.2 guidelines. The project is approximately 60,000 SF on two floors. The clinic is on one floor while the other floor will provide space for supporting functions such as a pharmacy, doctor\'s offices and other medically related operations. For the clinic, there are a host of exam rooms, offices and other treatment areas requiring small private rooms. The occupation of the perimeter of the plan for small offices and exam rooms on both floors limits access to both daylight and view. The Green Guide for Health Care (GGHC) acknowledges this fact and has created an alternate calculation for achieving daylight optimization. They have also modified the consideration of view to provide a ""Connection to the Natural World"" from 90% of ""areas of respite"". This CIR requests authorization from USGBC to utilize the EQ Credit EQ 8.1 from the ""Green Guide for Health Care"" in lieu of EQ Credit EQ 8.1 from LEED NC 2.2 for daylight. We propose meeting GGHC EQ Credit EQ 8.1a for 1 point, and meeting GGHC EQ Credit 8.1b for an Exemplary Performance credit. (GGHC Credit EQ 8.1 description and ""Suggested Documentation"" can be submitted upon request) Furthermore, we request authorization to use the GGHC EQ Credit EQ 8.2, ""Connection to the Natural World"" in lieu of LEED NC EQ Credit EQ 8.2, ""Views for 90% of Spaces"". (GGHC Credit EQ 8.2 description and ""Suggested Documentation"" can be submitted upon request) By using the GGHC EQ 8.1 and 8.2 we feel that this project meets the intent of this LEED credit." "The CIR requests an alternative compliance path for Indoor Environment Quality Credit 8.1 by meeting the requirements of Green Guide for Health Care EQ credit EQ 8.1a-b. Additionally the CIR requests an alternative compliance path for IEQ c8.2, but CIRs can only address one credit per CIR. Hence this ruling only covers EQ 8.1. EQ Credit 8.1 in Green Guide for Health Care does not have adequate criteria for daylighting to meet the intent of the LEED NC Credit 8.1; therefore this alternative compliance path cannot be granted equivalency within LEED NC." "None" "None"
"LEED Interpretation" "2019" "2008-01-29" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc8.1 - Daylight & views: daylight 75% of spaces" "The building in question will be a 200,000 square feet warehouse with a 300 square feet office space. The warehouse space will be used for storage of goods and materials that will be transported to an adjacent facility (within 1/8 of a mile) for use in product manufacturing. The employees of the warehouse facility will spend a majority of their day within the office space except for the occasional need to go out into the warehouse space to receive and stock incoming shipments, or transition of these goods and materials to the adjacent facility. As such, is the warehouse space considered ""regularly occupied"" space? If so, would the installation of roof mounted skylights providing a consistent illumination level of 25 footcandles throughout 75% of the warehouse space fulfill the requirements of this credit - if no exterior wall windows are provided? Please rule if this strategy would be consistent with the intent of this credit." "The CIR inquiry is posing two different questions. The first question is inquiring if a warehouse space that is largely unoccupied, with the exception of short term efforts to transfer stored materials, can be excluded from the requirements of this credit. The second question asks if horizontal skylights can be used in lieu of wall mounted windows to achieve the required 25 footcandle levels within the warehouse space. Per the submitted narrative, the workers that handle the warehouse materials are regularly assigned to office space elsewhere in the building and only occasionally enter the warehouse for the purpose of handling shipments. Under this specific case, the warehouse can be reasonably excluded from the requirements of the daylight calculations for the purposes of this credit. That said, the workers that enter the warehouse would benefit from daylighting if it is provided." "None" "None"
"LEED Interpretation" "5035" "2007-04-20" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc8.1 - Daylight & views: daylight 75% of spaces" "The glazing factor calculation is based in part on the window area of the space. In our project, the window head height is right at the ceiling, and the ceiling steps down about half way back into the space. Is it acceptable to use the actual window area in the calculation, or should the area be adjusted based on an ""effective"" window height? Can this effective height be the average ceiling height for the space? In other words, if the window head height is 10\' and the average ceiling height is 9\'-6"", should 9\'-6"" be used as the window height when calculating the window area? In summary, the area is roughly 94\'-0"" wide by 10\'-4"" with a ceiling height of 11\'-6"" before it drops down to a 9\'-6"" ceiling that is 19\'-6"" deep." "No, it is not acceptable to use the actual window area in the calculation in situations where the ceiling height drops down lower than the window height. The calculator used to show compliance under Option 1 is not set-up to take into account these kinds of geometries. In these kinds of situations, the effective window height must be used, i.e. the height of the lowered ceiling plane. Alternatively, the project team can elect to follow the compliance paths under Option 2 or 3 both of which are better suited to take into account the design situation described in this CIR request. Applicable Internationally. " "None" "None" "X"
"LEED Interpretation" "5148" "2008-09-05" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc8.1 - Daylight and views - daylight 75% of spaces" "LEED reference material does not give clear guidance on how to use analysis software for documentation, and we are simply asking for general clarification regarding technical requirements. The numbers below correspond to the analysis steps in the reference manual. From EQ 8.1 Option 2-Daylight Simulation Model: 1.Regarding materials, a problem comes up when we have a core and shell project where the reflectance values of internal materials are unknown. Could there be suggested default values to use in this instance? 2.The analysis grid 30"" off of the ground is reasonable but the reference manual does not describe placing an actual work plane in the analysis model. Without an actual work plane there can be instances where a floor-to-ceiling glazing allows light to bounce further into back than if the spaces were filled with furniture or desks. A recently published book on the subject states ""Since Option 2 LEED-NC Version 2.2 requires 25 foot-candles of daylight in 75% of regularly occupied areas at the workplane level.the simulation models should have the workplanes incorporated."" The image in this book shows a modeled workplane in the middle of the space with the caption ""A model used for qualifying for the LEED daylighting credit."" Nowhere in LEED literature have I found an indication that we should model the plane, though doing so will affect the results. 3.""Clear sky conditions at 12:00 noon on the equinox (March 21/September 21)"" is thought not to be technical enough by many experts. Perhaps LEED should cite using CIE Clear Sky as one option, or the Perez All-Weather Sky Model as another option, but with either it needs to specify how the location is defined: o If we use a CIE Clear Sky (static simulation) option we must find ""design sky illuminance"" values. There are many ways to find this value but we should have a clear indication of an accepted source(s. o If we use the Perez Model (static simulation) we incorporate actual weather data and our calculations are potentially more accurate. But with a static simulation we only calculate for 1 specific day and that day could be cloudy, so how could we approach this credit if we want our results based on weather data? Do we want our results based on weather data? It\'s our opinion that analysis tools are sophisticated enough that LEED should require dynamic simulations which calculate annual daylight autonomy values from weather data. 4.Item 4 proves misleading when you get to 5. 5.This allows us to include the percentage of the floor area above the threshold even if the entire room is not above, contrary to item 4. This misunderstanding has generated multiple CIRs already, none of which explain it clearly. Am I right to assume that all area above the threshold can be counted, as long as we define these areas separately? Option 3 is clearer about this issue. Item 5 also brings up a question of how to calculate the floor area from a grid of points. Some software programs do this for you but only after interpolating the values between points using contour lines. It should be explained how to derive compliant area based on point readings, and perhaps we should be warned that points falling within walls or columns will read ""0"" which throws off the data (your example image, Figure 2 on page 384 of LEED-NC 2.2 shows a reading of ""0"" for a point falls inside a column). Option 3-Daylight Measurement is also unclear about how to translate points into area, could you please be more specific?" "The applicant has submitted a multi-point question regarding guidance related to the use of analysis software for the documentation of the daylight distribution. The ruling is provided in order of the questions asked. 1. While there are no specific defaults that have been established by any modeling protocols for daylight simulation, it is reasonable to assume reflectance values similar to those used for calculating lighting fixture coefficients. For example, typical reflectance values could be 50% for walls, 20% for the floor and 80% for the ceiling. If known, actual values must be used. 2. Only the analysis grid is required. There is no need to model the actual work plane. 3. While this CIR cannot provide any specific rules for selection of the sky model to be used, both methodologies are acceptable as long as the applicant submits a narrative explaining the methodology in the submittal. 4. See item 5 below 5. a. The assumption made is correct. All area above the threshold can be counted, as long as these areas separately defined. b. Software analysis from grid points is acceptable, as long as the grid points do not fall in walls, columns and other elements that may return a null value and skew results. Adjustments and additional post processing calculations may be necessary to exclude these instances. Secondly, various simulation programs draw foot-candle or daylight factor iso-contours. This is the best way to understand which areas of a space meet or exceed the threshold. Again, adjustments may be necessary. While this ruling provides guidance to the applicant, it should be noted that there are no set modeling guidelines available for daylight analysis. For the purposes of this credit, it is expected that the person(s) responsible for the analysis have enough experience to make the most appropriate determination of the daylight analysis methodology." "None" "None"
"LEED Interpretation" "5203" "2009-05-12" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc8.1 - Daylight & views: daylight 75% of spaces" "We are currently designing an Army Reserve and National Guard facility in Columbus Nebraska. The unique client for this project mandates a strict adherence to facility Full Time Equivalents. By these guidelines, this 46,000 square foot facility will employ 6 full time people. However on a drill weekend, occurring once per month, this number inflates to approximately 180. Our question pertains to the definition of ""Regularly Occupied Spaces"" in EQ Credit 8.1 Daylight and Views. The space in question is the assembly hall. The unique nature of the facility\'s manning requirements only allow the assembly hall to be used approximately once per month, less than 4% of a normal business year. In response to such a low interval of use, the project has been mechanically zoned to minimize the energy used in this space. Additionally, Army guidelines do not authorize cooling in an assembly hall. Introducing more glass to this particular space does not align with the credit\'s intent, and adversely impacts our energy model. In summary, we would like to remove the assembly hall from our list of regularly occupied spaces in an attempt to satisfy not only EQ Credit 8.1, but to also improve long-term energy performance." "The project team is requesting whether the assembly hall of their project can be excluded from the list of regularly occupied space because of its part-time use and concerns over increased energy efficiency. The reference guide defines regularly occupied spaces to be spaces where people are seated or standing as they work, regardless of the frequency that occupation may occur. Additionally, this credit is not awarded based on the energy efficiency of a space, but on the daylight that is provided. A properly designed space can mitigate potential heat gain through glazing orientation, shading, high-performance glazing, and daylight controls. Assembly spaces often benefit from the introduction of daylight, and the project has not provided a compelling argument for the exclusion of the space from this credit. Applicable Internationally. " "None" "None" "X"
"LEED Interpretation" "752" "2004-04-19" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc8.1 - Daylight and views - daylight 75% of spaces" "In regards to LEED Credit 8.1 we would like a definition of regularly occupied spaces and critical visual task areas. Our building is an Institutional Building and therfore contains several spaces that are periodically occupied throughout the day such as, waiting rooms, training rooms, dinning rooms, reading rooms and family research area and a yoga room. We would like to know if these areas fall under the definiton of regularly occupied and critical visual task areas." "The issue of ""regularly occupied spaces"" has been previously addressed in EQ Credit 6.1 ruling dated 11/9/2001. In summary, it is difficult to have a finite definition of ""regularly occupied spaces"" as the programmatic needs for each building will vary, even for common types of spaces. For example, for one project, a waiting room may be considered a transition space only, akin to a lobby, but for another, it may accommodate a workspace and would therefore be classified as ""regularly occupied space"". If various occupants of the building use a space on a regular basis and daylight would not interfere with the tasks performed there, it would meet the criteria for spaces needed to be considered for this credit. Spaces such as training rooms, dining rooms, reading rooms and research areas appear to meet the criteria as they are regularly occupied and would typically benefit from the introduction of daylight. If any space is to be excluded from the calculations, provide a brief narrative to explain rationale and assumptions. Applicable Internationally. " "None" "None" "X"